Chemistry in the Kitchen: Reactions and Enzymes
XII. Reactions and Enzymes
A. Chemical Reactions
1. Nature of Reactions
a. breaking a bond and making a new bond = chemical reaction
b. Is melting ice or dissolving sugar in water a chemical reaction?
2. Types of reactions
a. reactants --> products
b. four kinds of chemical reactions:
i. isomerization
ii. addition/decomposition
iii. transfer
3. Energy requirements
a. covalent bonds resisty change
b. before a reaction occurs, the molecules must gain ____________________ to reach the high-energy _____________________ .
c. energy diagram:
d. What is potential energy?
4. Collisions and Activation Energy
a. amount of potential energy depends on how fast the molecules collide
b. slow collision:
c. fast collision:
d. How does kinetic energy become potential energy?
5. The Transition State
a.
b. energy diagram of transition state:
6. Stability of molecules
B. Enzyme Action
1. Catalysis
a. enzymes speed reactions by:
b. energy diagram:
2. Enzyme Specificity
a. quite specific: converts a distinctive set of reactant molecules into distinctive products.
b. specificity arises because of the shape of the molecule
c. substrates:
d. active sites:
3. The Catalytic Cycle
a. substrate binds to active site
b. products released
c. Do enzymes really change their shape when substrates bind?
d. What holds the enzyme and substrate together?
4. How Enzymes Act
a. single step converted to multiple, lower energy steps
C. The Nature of Digestion
1. Intro
a. continuous tube that includes:
b. four basic functions:
i.
ii.
iii.
iv.
2. the human digestive system
a. the mouth
b. the stomach
c. the small intestine
anatomy of the intestine:
d. the colon